Abstract:

Type 1 diabetes (T1D) is becoming more and more prevalent in the Western world and the incidence of T1D is the highest in Finland. The pathogenesis and etiology remain unknown but environmental factors are believed to trigger and drive the disease process in genetically susceptible individuals. An extensive amount of different samples, including skin swab samples, have been collected in the DIABIMMUNE study, which aims to elucidate the correlation of TD1, celiac disease (CD) and allergies with a range of different factors. The aim of the present study is to develop sampling tools that allow the isolation and identification of cutaneous viruses.

The focus of the study was on the polyomaviruses, which are small, non-enveloped icosahedral DNA-viruses about 40 – 45 nm in diameter. There are 13 currently known human polyomaviruses. Eleven of these have been found since 2007. Polyomaviruses cause problems in immunocompromised people e.g. transplant patients and the elderly. Polyomaviruses are versatile and occur throughout the body, on skin, in respiratory tract and in renal cells from where they are secreted in urine.

Forty-nine healthy volunteer subjects in the age range 22 - 65 were included in the study and the skin swabs were taken from forearm, inner elbow, behind the ear and forehead. A blood sample was also taken and serum antibodies to viruses were monitored. After DNA extraction, the DNA of 13 human polyomaviruses were amplified with PCR and the products were detected with a Luminex-based assay. Rolling-circle amplification was tested prior to the PCR, but it did not increase the number of positive samples. Additionally, sera were used to study serological responses for the three clinically most significant polyomaviruses, JC polyomavirus (according to the initials of the first patient, JCPyV), Mercel cell polyomavirus (MCPyV) and Trichodysplasia spinulosa polyomavirus (TSPyV).

MCPyV had the highest geno- and seroprevalence of 67 % and 83 %, respectively. The genoprevalence for polyomaviruses 6 and 10 were 22 % and 35 %, respectively, and less than 9 % for other polyomaviruses. Polyomaviruses JC, BK (according to the initials of the first patient), 9, 11, 12 and 13 were not detected. The seroprevalence for JCPyV was 48 % and for TSPyV, 67 %. The amount of positive samples varies between sampling sites. MCPyV was least common in the sample taken from behind the ear and PyV6 and PyV10 were least common in the inner elbow, however, the differences were not statistically significant. Other viruses were so rare that no conclusions about their preferred sites could be made.

The results showed that it is possible to isolate and detect viruses by Luminex-PCR from skin swab samples. Forehead and forearm were promising places to take skin swab samples, as the genoprevalence was the highest in these sites and in addition, the sites are easy to sample. The methods used in this study can be used to analyze polyomaviruses in DIABIMMUNE skin swabs to investigate possible differences in the presence of cutaneous viruses in children in Finland, Russian Karelian and Estonia.Tyypin 1 diabetes (T1D) yleistyy länsimaissa jatkuvasti ja maailmanlaajuisesti korkein esiintyvyys on Suomessa. Diabetekseen sairastumisen syytä ei vielä tiedetä, mutta ympäristön vaikutusta pidetään todennäköisenä tautiprosessin alkamisessa ja etenemisessä geneettisesti alttiilla ihmisillä. DIABIMMUNE-tutkimus pyrkii selvittämään useiden eri tekijöiden vaikutusta allergioihin, keliakiaan ja T1D:een. Tutkimuksen puitteissa on kerätty valtavasti aineistoa, kuten ihosivelynäytteitä. Tämän työn tarkoituksena oli tutkia ihosivelynäytteiden ottoa ja analyysiä.